The primary aim of this study is to determine whether four cycles of Taxol given after four cycles of postoperative Adriamycin (A) and cyclophosphamide (C) will more effectively prolong disease-free survival and survival than do four cycles of postoperative AC alone in patients with operable breast cancer who have one or more histologically positive axillary lymph nodes. Patients should have no evidence of metastatic disease and should have undergone either lumpectomy plus axillary node dissection or total mastectomy plus axillary node dissection. Following stratification by number of positive axillary nodes, tamoxifen administration, and type of surgery, patients will be randomly assigned to one of two groups. Group I will receive four cycles of A and C given at 60 mg/m2 and 600 mg/m2, respectively, every 21 days. Group II will receive four cycles of AC as in Group I, followed by four cycles of Taxol given at 225 mg/m2 as a 3-hour infusion every 21 days. Beginning on the first day of administration of their assigned chemotherapy, patients >/=50 years of age and those <50 years of age with tumors that are ER-positive or PgR-positive will receive tamoxifen at 20 mg p.o. once daily for at least 5 years. All patients in both groups who undergo lumpectomy will receive postoperative radiotherapy after completion of their assigned chemotherapy and after any toxicity has resolved. The objective of this study is to determine whether four cycles of postoperative Taxol given after four postoperative AC will more effectively prolong disease-free survival and survival than will four cycles of postoperative AC alone in patients with operable breast cancer and histologically positive axillary nodes.